1. Field of the Invention
The invention relates in general to a system for manufacturing a micro-retarder and a method for manufacturing the same, and more particularly to a system for manufacturing a micro-retarder by way of heat treatment and a method for manufacturing the same.
2. Description of the Related Art
Referring to FIG. 1, a perspective of a conventional method for manufacturing a micro-retarder 910 is shown. The micro-retarder 910 is a key parts of a 3-D display device. As indicated in FIG. 1, the polymolecule film 911 is optically anisotropic in its molecule structure, which induces optical anisotropism on the material. Optical phase delay between different axes occurs after the polarized light passes through the polymolecule film 911. The conventional method for manufacturing the micro-retarder 910 heats a particular partial area of the polymolecule film 911 by a heating source 930 so as to resume the polymolecule film 911 to be optically isotropic. The heated partial area 910a is alternated with the unheated partial area 910b, thereby forming a micro-retarder 910.
Referring to FIG. 2, a perspective of a polarized light L9 passing through a micro-retarder 910 is shown. The polarized light L9 is split into two polarized directions after passing through the micro-retarder 910. When the polarized light L9 passes through the heated partial area 910a, optical phase delay does not occur to the polarized light L9. When the polarized light L9 passes through the unheated partial area 910b, optical phase delay occurs to the polarized light L9. When the quantity of the optical phase delay is selected as π and the angle between the direction of the polarized light L9 and the optical axis of the phase retarder plate 911 is 45 degrees, the polarization direction of the polarized light L9 after passing through the unheated partial area 910b will be rotated by 90 degrees. As indicated in FIG. 2, the polarization directions of the light passes through the heated partial area 910a and unheated partial area 910b become orthogonal to each other. Thus, the micro-retarder 910 can be applied in a 3-D display device to create a 3-D image effect.
Referring to FIG. 3, a retardation curve of a micro-retarder 910 fabricated by a conventional method is shown. In FIG. 3, the X-axis denotes position, and the Y-axis denotes phase delay. When the conventional heating source 930 heats the polymolecule film 911, the heating energy is distributed unevenly and heating energy diffuses.
Referring to FIG. 4. FIG. 4 shows a cross-sectional energy distribution diagram of the laser light adopting TEM00. Particularly, when the laser beam adopting TEM00 is used as a heating source 930, the energy distribution is a Gaussian distribution curve where the energy in central area is higher than that in the peripheral area. Thus, the distribution of the heating energy becomes even more uneven. As indicated in FIG. 3, the change between the heated partial area 910a and the unheated partial area 910b is depicted by a smooth curve not a steep line. That is, the phase delay in the border of the heated partial area 910a is not significantly different from that in the unheated partial area 910b. Thus, the conventional micro-retarder 910 will result in problem of poor stereo contrast.